• 한국대기환경학회지
• /
• 제27권4호
• /
• pp.379-386
• /
• 2011

Catalyst-assisted plasma system with a DBD (Dielectric Barrier Discharge) reactor was used to remove hydrogen sulfide, which is one of the odorous species in this study. The ${\gamma}-Al_2O_3$ and ${\beta}$-Zeolite catalysts impregnated by Ag, Cu and Mn species were employed as catalysts and their $H_2S$ removal characteristics under plasma irradiation were investigated. From the experimental study, we found that the $H_2S$ removal efficiency increases with decreasing space velocity in the system and increasing specific input energy. Furthermore, ${\beta}$-Zeolite catalysts are efficient to remove $H_2S$ than ${\gamma}-Al_2O_3$ catalysts. Especially, the catalysts impregnated by Ag have higher removal efficiency than other catalysts (Cu, Mn).

• 환경위생공학
• /
• 제4권2호
• /
• pp.33-45
• /
• 1989

The survey was conducted on the actual conditions of species, the facilities, a establishment of regulation concerning laboratory animals and the related problems on users and suppliers of laboratory animals in Korea. The questionnaires were sent to 430 and received from 107$(24.9\%)$ places. The results obtained were as follows : 1. Experimental animals used at the 107 places were 21 species: mouse(90\;places,\;84.1\%)$, rat $(61,\;57.0\%)$, rabbit$(76,\;71.0\%)$, guineapig$(42,\; 39.3\%)$ etc. 2. The main organizations using laboratory animals were university $46(43.0\%)$, institute $32(29.9\%)$ and pharmaceutical company $27(25.2\%)$ etc. 3. Most the laboratory animal facilities in Korea have been conventional system without environmental controls, but a few places have been recently established barrier system. 4. To get a good experimental result, a regular genetic and microbiological monitoring of laboratory animals should be done. 5. It was required that a educational facilities and a quality test agency for laboratory animals should be established. 6. It was also required that a regulation for breeding and using of laboratory animals should 'be enacted.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2017년도 9th Asian Crop Science Association conference
• /
• pp.233-233
• /
• 2017

Algal communities are important to maintain the aquatic ecosystems function. Algae have short life cycles, they respond quickly to environmental change and their diversity and density can indicate and the quality of their habitat. The bloom forms before the rice seedings have emerged, it may present a physical barrier that prevents the seedlings from penetrating the floodwater. Wind may also move the algal bloom, pushing the young plants beneath the surface. Another harmful action develops when the water dries up and the algae form a layer at the bottom of the field. The layer envelops the seedlings, which are not yet deeply rooted, and drag them to the surface when the water is let in again. Soil utilization pattern can be the mail facter affecting soil physico-chemical properties, especially in soil phosphorus (P). Solid content of the algae culture solution increased with the increase in the nitrogen rather the phosphors concentration. Phosphoric acid was treated with conventional treatments (100-0%, before transplanting time-tillering stage), 50-50%, 0-100%, and un-treated. The herbicide was treated on the 7 DAT (day after transplanting). Green algae samples were collected 20 DAT. Total phosphoric acid was the highest at 0.06 in 50-50% treatment in 20 DAT. The amount of green algae was about twice (9.8 mg/20ml) that of un-treated. Total number of green algae was 54 species(Green algae 35 species, Euglena 9 species, Stone wheel 10 species). Among the phosphoric acid treatment methods, the number of occurrences of green algae were the highest with 39 species in 0-100%, followed by 50-50%, 28 species, conventional treatments, 22 species, non-treatment, 18 species, respectively. Rice Yield was not significantly different by phosphoric treatment time, but slightly higher than un-treated. The maximal algal biomass was observed about 2weeks or 1 month after transplanting; the subsequent decrease of the biomass was related to the consumption by grazers and to a deficient light under the rice canopy. Maximal algal growth was observed just before tillering. To estimate the suitable method of phosphorus application in puddled-soil drill seeding of rice, available phosphorus appearance of algal water bloom, and rice yield were investigated in paddy soil of rice-barley double cropping system.

• 한국산학기술학회논문지
• /
• 제18권9호
• /
• pp.76-83
• /
• 2017

어류는 빛에 대해 민감한 반응을 보이므로 이를 이용한 어류 관리 기술 개발이 필요하다. 따라서 본 연구에서는 빛을 이용한 어류 차단 시설을 개발하였으며 국내 대표 외래어종인 배스와 블루길을 대상으로 조도 차이를 이용한 차단 효과를 분석하였다. 빛은 발광 다이오드를 이용해 발생시켰으며 바닥에서 수직 방향으로 향하게 설치하였다. 유속은 어류의 소상능력을 고려하여 총 3단계(0.2, 0.1, 0.05 m/s)로 구분하였으며 학습효과를 방지하기 위해 양육수조에서 1일 이상 휴식한 어류를 대상으로 실험하였다. 실험은 차단시설 적용 시 소상하는 어류 개체수와 차단시설 종료 후 소상하는 개체 수를 비교하는 방식으로 수행하였으며 차단 시설의 효과를 높이기 위해 일몰 후 수행하였다. 실험 결과 조도 차이에 따른 어류 차단효과는 높았으며 전반적으로 배스의 차단율이 블루길보다 낮았다. 전체 실험 개체수를 기준으로 배스의 차단율은 96.33%, 블루길의 차단율은 99.00%이며 소상 개체수를 기준으로 하면 배스는 91.73%, 블루길은 98.73%로 나타났다.

• 한국물환경학회지
• /
• 제30권2호
• /
• pp.175-183
• /
• 2014

The influence of temperature on the treatment efficiency of chlorinated organic substances contained in groundwater by permeable reactive barrier which is composed of $Fe^{\circ}$ has been investigated by constructing the Pourbaix diagrams for Fe-$H_2O$ system at different temperatures based on thermodynamic estimation. In aerobic condition, the equilibrium potentials for $Fe^{\circ}/Fe^{2+}$ and $Fe^{2+}/Fe^{3+}$ were observed to increase, therefore, the dechlorination reaction for organic pollutants by $Fe^{\circ}$ was considered to decline with temperature due to the diminished oxidation of reactive barrier. The result for the variations of the ionization fraction of $Fe^{2+}$ and $Fe^{3+}$ ion in the pH range of 0 ~ 2.5 obtained by employing Visual MINTEQ program showed that the ionization fraction of $Fe^{2+}$ increased with pH, however, that of $Fe^{3+}$ decreased symmetrically and the extent of the variation of ionization fraction for both ions was raised as temperature rises. The equilibrium pH for $Fe^{3+}/Fe(OH)_3$ was examined to decrease with temperature so that the treatment efficiency of chlorinated organic substance was expected to decrease with temperature due to the enhanced formation of passivating film in aerobic condition. The change of the reactivity of a specific chemical species with temperature was defined quantitatively based on the area of its stable region in Pourbaix diagram and depending on this the reactivity of $Fe^{3+}$ was shown to decrease with temperature, however, that of $Fe(OH)_3$ was decreased monotonously as temperature is raised for $Fe^{3+}/Fe(OH)_3$ equilibrium system. In anaerobic condition, the equilibrium potential for $Fe^{\circ}/Fe^{2+}$ was observed to rise and the equilibrium pH for $Fe^{2+}/Fe(OH)_2$ were examined to decrease as temperature increases, therefore, similar to that for aerobic condition the efficiency of the dechlorination reaction for organic substances was considered to be diminished when temperature rises because of the reduced oxidation of $Fe^{\circ}$ and increased formation of $Fe(OH)_2$ passivating film.

• 생명과학회지
• /
• 제32권7호
• /
• pp.550-566
• /
• 2022

뇌졸중은 세계적으로 사망과 장기간인 신체적, 인지적 장애의 주요 원인들 중 하나이며, 매년 약 1,500만명의 사람들에게 영향을 미친다. 뇌졸중의 병태 생리학적 과정은 다수의 사건들이 관여하는 복잡한 과정으로, 그 중 혈액-뇌 장벽(blood-brain barrier: BBB)의 붕괴는 허혈성 뇌손상의 진행에 크게 기여하는 것으로 알려져 있다. 따라서 BBB 붕괴는 뇌졸중의 특징으로 인식되므로 허혈성 뇌졸중에서 BBB 기능 장애를 보호할 수 있는 새로운 치료 전략을 개발하는 것이 뇌졸중 치료에 매우 중요하다. 전통한약은 천연물로 구성되어 있으며, 이는 뇌졸중 치료약 개발을 위한 유망한 원천이 될 수 있다. 실제로 여러 연구에서 뇌졸중에 대한 한의학의 효능이 밝혀져 허혈성 뇌졸중에 대한 한의학적 치료 가치가 부각되고 있다. 본 리뷰에서는 허혈성 뇌졸중으로 인한 BBB 붕괴에 대한 전통적인 한의학의 처방, 탕약, 약재 및 활성 성분의 개선효과에 관한 현재 정보와 기본 메커니즘을 요약 정리하였다. 이러한 연구가 한의학의 신경보호 효과에 대한 추가 조사를 촉진하고 뇌졸중 환자에 대한 한방유래의 임상시험 시행을 활성화하는데 도움이 되기를 기대한다.

• Journal of Microbiology and Biotechnology
• /
• 제27권6호
• /
• pp.1163-1170
• /
• 2017

Clostridium difficile releases two exotoxins, toxin A and toxin B, which disrupt the epithelial cell barrier in the gut to increase mucosal permeability and trigger inflammation with severe diarrhea. Many studies have suggested that enteric nerves are also directly involved in the progression of this toxin-mediated inflammation and diarrhea. C. difficile toxin A is known to enhance neurotransmitter secretion, increase gut motility, and suppress sympathetic neurotransmission in the guinea pig colitis model. Although previous studies have examined the pathophysiological role of enteric nerves in gut inflammation, the direct effect of toxins on neuronal cells and the molecular mechanisms underlying toxin-induced neuronal stress remained to be unveiled. Here, we examined the toxicity of C. difficile toxin A against neuronal cells (SH-SY5Y). We found that toxin A treatment time- and dose-dependently decreased cell viability and triggered apoptosis accompanied by caspase-3 activation in this cell line. These effects were found to depend on the up-regulation of reactive oxygen species (ROS) and the subsequent activation of p38 MAPK and induction of $p21^{Cip1/Waf1}$. Moreover, the N-acetyl-$\text\tiny L$-cysteine (NAC)-induced down-regulation of ROS could recover the viability loss and apoptosis of toxin A-treated neuronal cells. These results collectively suggest that C. difficile toxin A is toxic for neuronal cells, and that this is associated with rapid ROS generation and subsequent p38 MAPK activation and $p21^{Cip1/Waf1}$ up-regulation. Moreover, our data suggest that NAC could inhibit the toxicity of C. difficile toxin A toward enteric neurons.

• 한국물환경학회지
• /
• 제30권4호
• /
• pp.394-402
• /
• 2014

High-voltage dielectric discharges are an emerging technique in environmental pollutant degradation, which are characterized by the production of hydroxyl radicals as the primary degradation species. The initiation and propagation of the electrical discharges depends on several physical, chemical, and electrical parameters such as 1st and 2nd voltage of power, gas supply, conductivity and pH. These parameters also influence the physical and chemical characteristics of the discharges, including the production of reactive species such as OH, $H_2O_2$ and $O_3$. The experimental results showed that the optimum 1st voltage and oxygen flow rate for RNO (N-Dimethyl-4-nitrosoaniline, indicator of the generation of OH radical) degradation were 160 V (2nd voltage of is 15 kV) and 4 L/min, respectively. As the 2nd voltage (4 kV to 15 kV) was increase, RNO degradation was increased and, generated $H_2O_2$ and $O_3$ concentration were increased. The conductivity of the solution was not influencing the RNO degradation, $H_2O_2$ and $O_3$ generation. The pH effect on RNO degradation was not high. However, the lower pH and the conductivity, the higher $H_2O_2$ and $O_3$ generation were observed.

• 한국정보통신학회논문지
• /
• 제7권7호
• /
• pp.1563-1568
• /
• 2003

국제환경기구(GEF)의 해양환경 위해 지정 대상의 하나인 선박안정수 처리기술로써, 선박 안정수에 포함되어 타 지역으로부터 이동되는 유해성외래침입생물 처리방안을 제안하였다 alpha-AL$_2$O$_3$ 유전장벽층 전극에 의한 강 전리방전 기술을 적용하여 주위 산소와 물분자로부터 고농도 수산자유기(OH : hydroxyl radical) 및 활성입자( OH, $O_2$＋, O (1D), HO$_2$)를 전리, 발생시켜서 이들을 해수에 신속히 용해 확산시켜 비교적 낮은 ∼20mg/L 정도의 수산기농도 하에서 유해성외래침입생물을 소멸 처리하는 환경 친화적 녹색 청정 처리기술이다. 제안된 기술은 대상물의 처리 후 부수적으로 발생할 수 있는 처리잔류물이 전혀 발생하지 않으며, 인공적 화학성분의 약제를 사용하지 않는 저렴한 처리방법으로 대ㆍ소형 원양선박의 안정수에 포함되어 있는 유해성외래침입생물의 타 지역 해양확산을 방지하고 안전하게 처리할 수 있는 자연치유적 신기술이다.

• 한국산학기술학회논문지
• /
• 제10권3호
• /
• pp.607-612
• /
• 2009

생태방음벽에 있어서 구조도 중요하지만, 식물종자의 발아와 생장율을 고려한 선택도 매우 중요하다. 재래종과 외래종 35종을 선발하여 온도 $24^{\circ}C$, 습도 60%, 그리고 12시간 주기로 낮과 밤을 조절하였고, 식생기반재로 일반토양과 유기물 토양의 비율을 6:4, 7:3, 8:2, 9:1로 하여 실험하였다. 실험한 종 중 8종은 2주 동안 발아하지 않았지만 그 외 나머지 종들은 시간차를 두고 모두 발아하였다. 가장 발아율이 좋은 종은 Perennial penant(92 %)이고 다음은 Brassica napus(86%), 그리고 Silene armeria(82 %) 순으로 나타났다. 본 연구에서는 발아한 종의 뿌리 및 줄기의 길이를 측정하여 분석하였다. 이번 연구에서 뿌리의 생장이 가장 좋은 3종 Perennial penant, Perennial sonata Rebolsentri가 생태방음벽 개발에 가장 적합한 종으로 사료된다.